BIO 446L 1st Edition Lecture Outline of Last Lecture I. Membranea. The plasma membraneb. Movement acrossII. Major Organellesa. ribosomesb. Endoplasmic reticulumc. Golgi apparatusd. Cell granulesi. Zymogenii. Lysosomeiii. Proteosomeiv. PerioxisomeIII. Cytoskeletona. Microtubulesb. Microfilamentsc. Intermediate filamentsIV. Nucleus and nuclear envelopea. Chromatin and chromosomesb. nucleolus Outline of Current Lecture I. Epithelial Tissuea. Characteristicsb. Basal lamina and basement membranec. Intercellular (lateral)i. Transportd. Structures on the apical surfacei. Microvillie. Structures on all epithelial surfacesi. InterdigitationsCurrent LectureEpithelial Tissue- CharacteristicsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Secrete and absorbo Myoepithelial cell= contractileo Apical= facing externalo Basolateral= facing basement membraneo Everything entering/leaving must pass a layer of epithelium- Basal lamina and basement membraneo Hemidesmosomes= aggregates of integrins Allows epithelial cell to attach to basal laminao Electron dense layer= collagen type IV, binding sites for integrinso Basal lamina anchored to reticular lamina (type III collagen) by anchoring fibers (type IV collagen)- Intercellular (lateral surface) connectionso Tight junctions= most apicalo Adhering junctions= most basalo Desmosome= patches of fiber connecting one cell to the nexto Occludin= very tight proteins forming a barrier and inhibits transport from apical to intercellular spaceo Transport across epithelia Aquaporins= water channels- Some water is endocytosed and some diffuseso Cadherin= glycoproteino Catenin= intracellular proteino Gap junctions= pores channels between two cells Connexons= formed by connexin proteins Gap junctions cluster to allow very rapid communications between cells- Structures on the apical surface of epithelial cellso Microvilli= striated or brush on intestinal cells Lots of surface area Absorption/digestion Extremely regular structure Celiac disease= destroys microvilli and decreases absorption and digestion of nutrientso Clilia= mostly in respiratory tract Also flagella on sperm Most are mobile- Usually by dyenins- Structures on the epithelial surfaces of cell structures for absorptiono Interdigitations= lateral Share cytoplasm with gap junctions and increase surface area for transporto Mitochondria= arranged on basal side Produce ATP needed for transport at basal surface into
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